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Fewer Heat Shield Dings on Shuttle Discovery
According to NASA, the amount of damage to thermal tiles noted on Discovery was significantly lower after the latest mission. According to the report, there was a 33% reduction in the number of dings on the belly of the orbiter and an almost 50% reduction in the number of hits greater than one inch. This would seem to indicate that the new foam is working better. "The vehicle looked very good," Thomas Ford, a member of NASA's ice-debris inspection team at Kennedy Space Center, said Wednesday. "It's definitely gratifying."
The heat shields are shaped so the hot regions of the gas are kept away from the shield.
The problem isn't the heat, but the pressure (that causes this heat as a side effect).
During re-entry, the shuttle travels supersonic thereby preventing the air to get out of the way fast enough.
Actually, a female astronaut commanded the Return to Flight expedition, also aboard Discovery, which was also a very "clean" flight in terms of the tile damage.
Actually, this has been a problem since the first launch. Maybe you are to young to remember, but there was a lot of tension for the first shuttle re-entry, because there were tiles missing, apparently lost/damaged during launch. It all worked out ok, so, the attitude became 'oh, lose a few is no big deal'. Eventually it became a big deal.